28 July 2005
measurements of 12 x 12 ft (3.7 by 3.7 m) at the base, while the top deck is 5 ft (1.5
m) wide and 10 ft (3 m) long. If small stair platforms are built alternately opposite
hand, the requirement for a large platform can be met by lashing two of the smaller
ones together. Sometimes the ship end of the brow can be connected to a rotatable
platform which is permanently fixed to the ship by means of pins that lock the brow
pivot hooks to the circular rotating portion of the rotatable platform. Construction
materials and live load requirements are the same as for brows.
BROW AND PLATFORM DESIGNS.
Standard designs for brows and platforms are found in NAVFAC Dwg SD1405000-
1405041 and may be obtained from NAVFAC EICO.
WALKWAY OR CATWALK.
These are permanent personnel access bridges installed between shore and
different elements of piers and wharves. One example is a walkway between the
pier or wharf structure and a mooring dolphin located some distance away as shown
in Figure 2-1.
For walkways between shore and a U-shaped wharf, a 4-ft (1.2 m) width is
recommended. For infrequently used walkways, the minimum width should be 3 ft
Design all walkway structures for 100 lbs./ft2 (488 kg/m2) live load.
may be wood, aluminum, or fiberglass members. In view of the light loads
encountered, piles supporting deck stringers can be of treated timber. Where loads
and installation difficulty make timber piles inadequate, concrete and steel piles may
Provide handrails on either side of the walkway. Consider handrails for use along
edges of approach trestles and along non-berthing extents of docks or wharves.
Transfer bridges or ramps are sometimes required for moving vehicles or heavy
cargo from ships, similar to a roll-on/roll-off (RO/RO) operation. MSC RO/RO ships
do not require any special features on existing Navy piers. Sideport ramps are